Why return loss should be less than 10 dB for antenna?
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Why return loss should be less than 10 dB for antenna?
The return loss measures the reflected wave to the incident wave, that is RL = -20 log(Γ). So, a return loss of -10 dB means that the reflected wave is 10 dB lower than the incident wave. This is approximately equal to a reflection coefficient of 0.3, so 30\% of the incident wave is wasted.
What is 10 dB in return loss?
Return Loss & VSWR Table
| Return Loss in dB | What It Means | VSWR Number |
|---|---|---|
| 8 dB | 16\% reflection, 84\% power into the antenna | 2.3 |
| 10 dB | 10 dB (10\% reflection, 90\% power into the antenna) | 2 |
| 15 dB | 15 dB (3\% reflection, 97\% power into the antenna) | 1.4 |
| 20 dB | 20 dB (1\% reflection, 99\% power into the antenna) | 1.2 |
What is good return loss for antenna?
While different systems have different acceptable return loss limits, 15 dB or better is a common system limit for a cable and antenna system.
Should return loss be high or low?
Return loss is related to both standing wave ratio (SWR) and reflection coefficient (Γ). Return loss is a measure of how well devices or lines are matched. A match is good if the return loss is high. A high return loss is desirable and results in a lower insertion loss.
Why return loss should be less than?
You want all of your energy going out the antenna, and not bouncing back from bad matches. So having 10\% or less bouncing back is a good starting point. 0 dB return loss means there is no loss in the bounce back, the return = what was sent. This is what you would get with an open circuit or a short circuit.
Why is high return loss good?
Return loss is a measurement parameter that expresses how well a device or line matches. A high return loss is advantageous as it will result in a lower insertion loss.
Why is return loss important?
What is return loss dB?
What is Return Loss? The measurement of the amount of light reflected back toward the source is called return loss, and it is expressed in decibels (dB). This measurement parameter is always a positive number, and a high return loss is a favorable measurement parameter that generally correlates to a low insertion loss.
What is antenna return loss?
An antenna’s Return Loss is a figure that indicates the proportion of radio waves arriving at the antenna input that are rejected as a ratio against those that are accepted. Thus, a proportion of the radio waves will be reflected back down the transmission line from the antenna input flange connection.
Why is return loss important in antenna?
Return Loss is significant to radio system designers for a number of different reasons: If a large proportion of the incident radio waves are rejected by the antenna, this represents a loss of signal and the antenna efficiency is therefore reduced.
What is a good return loss for an antenna?
Therefore, any antenna presenting less than 6 dB return loss should be avoided. This results in ~ 10 \% reflected power and ~ 0.46 dB mismatch loss. The bottom line for most communication systems is that a return loss much above 10 dB represents a diminishing improvement in mismatch loss.
What does a 6 dB return loss mean?
In the case of a 6 dB return loss, this is equivalent to 0.5 reflection coefficient: This text is intended to illustrate the impact of return loss on antenna selection for non RF engineers. The key take aways are: When selecting or matching an antenna make sure the return loss does not drop below 6 dB at any frequency in your operating band.
What is the minimum received power of an antenna?
Or maybe the minimum received power for an antenna system to work is specified as -70 dBm (decibels relative to a milliWatt). Or the transmit power of your cell phone is given as -3 dB. Why is this? Why don’t they just tell you how much power is transmitted in Watts or the gain of an antenna in regular (linear) units?
What should I look for when selecting an antenna?
When selecting or matching an antenna make sure the return loss does not drop below 6 dB at any frequency in your operating band. An antenna return loss above 10 dB typically represents diminishing returns in performance.